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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <div class="col-md-4">

        <div class="row">

            <div class="col-md-2">a</div>

            <div class="col-md-2">b</div>

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    <div class="col-md-4">2</div>

    <div class="col-md-4">3</div>
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